The invention relates to a deflection yoke for use in a television receiver, and in particular, to a deflection yoke which permit its inclination relative to a cathode ray tube to be adjusted and hence is preferred for use in a color television receiver.
Three electron guns in a cathode ray tube are disposed at proper angles so that they are focussed at the center of a shadow mask. For example, three electron guns in an in-line array are disposed on a common horizontal plane in a manner such that beams therefrom accurately impinge on three dots of red, green and blue color located adjacent to each other at the center of a screen.
However, in cathode ray tubes which are in practical use, it is difficult to locate and secure the electron guns in this accurate position and array during the assembly, but a certain tolerance must be accommodated for, with consequence that when a deflection yoke is mounted on the neck of the cathode ray tube and placed against the bulb portion thereof before it is secured, the three electron beams from the three electron guns may not impinge correctly upon predetermined color dots. Thus a convergence distortion results. The convergence can be greatly improved by an adjustment of the inclination of the deflection yoke itself or the inclination of the axis of the deflection yoke relative to the axis of the cathode ray tube.
At this end, U.S. Pat. No. 3,921,110 issued to H. Ishii et al and entitled "Deflection Yoke Holding Device" discloses the use of a holder mounted on the front of a deflection yoke and which permits the deflection yoke to be secured in any inclination so as to correct a convergence distortion in order to produce an optimum raster. However, the use of such a holder results in an increase in the cost of the deflection yoke.